From: ptkwt@...1.aracnet.com (Phil Tomson)
Date: 2002-09-13T05:40:53+09:00
Subject: Re: not grasping the method overloading/multi-dispatch thing

In article <20020912151951.T25425@atdesk.com>,
Paul Brannan  <pbrannan@atdesk.com> wrote:
>On Fri, Sep 13, 2002 at 03:40:42AM +0900, Phil Tomson wrote:
>> Currently if we need a method that does two different things based on 
>> the type of an argument we have to do:
>> 
>>   def meth(s)
>>     case s
>>     when Integer
>>       #do something
>>     when Float
>>       #do something else
>>     end
>>   end
>
>This isn't necessary; see Hal's example of another alternative (declare
>a method in the Integer and Float classes that gets called from meth(),
>so that meth() follows the same code path for whatever type you use).

Good point.

>The downside is that you have to modify those classes in order for this
>to work.
>

In Ruby it's not really considered a downside... it seems to be an 
acceptable practice.

Perhaps this idea should be proposed as an idiomatic way of 
solving the problem - ie. "We don't need multi-methods since all classes 
are open in Ruby".

Phil